Invention name: Sliding gate
Technical field
[0001]
　The present invention relates to a sliding gate that adjusts the flow rate of the molten metal in the process of injecting the molten metal from the ladle to the tundish or from the tundish to the mold in the continuous casting of the molten metal such as steel. Specifically, the present invention relates to a method of swirling a molten metal flow by using a sliding gate.
　The present application claims priority based on Japanese Patent Application No. 2018-075947 filed in Japan on April 11, 2018, the contents of which are incorporated herein by reference.
Background technology
[0002]
　In continuous casting of molten metal such as steel, as shown in FIG. 1, the molten metal 21 is injected from the ladle 14 into the tundish 15, and the molten metal 21 is further injected from the tundish 15 into the mold 16. In the injection process of each molten metal 21, a sliding gate 1 is used to adjust the flow rate of the molten metal 21. The sliding gate 1 is usually composed of two or three plates 2, and each plate 2 is provided with a flow path hole 6 through which the molten metal 21 passes. 10 and 11 show a case where the sliding gate 1 is composed of three plates. It is possible to slide between the plates that come into contact with each other, and one of the three plates is provided so as to be movable along the sliding surface 30, and is called a slide plate 4. The remaining two plates 2 do not move relative to the ladle 14 or the tundish 15 to which the sliding gate 1 is attached, and are called fixing plates (upper fixing plate 3, lower fixing plate 5). By sliding the slide plate 4, the opening area of ​​the opening that overlaps the flow path holes 6 between the adjacent plates 2 (fixing plates) is adjusted, thereby adjusting the flow rate of the molten metal 21 and sliding. The gate 1 can be opened and closed. FIG. 10 shows a case where the opening is fully open, and FIG. 11 shows a case where the opening is 1/2 opening.
[0003]
　An injection pipe 11 such as a long nozzle 12 is provided in the lower part of the sliding gate 1 provided at the bottom of the ladle 14. When the molten metal 21 flowing out of the sliding gate 1 of the ladle 14 is injected into the tundish 15, it is guided into the tundish 15 via a flow path inside the injection pipe 11. Further, an injection pipe 11 such as a dipping nozzle 13 is provided in the lower part of the sliding gate 1 provided at the bottom of the tundish 15. When the molten metal 21 flowing out of the sliding gate 1 of the tundish 15 is injected into the mold 16, the molten metal 21 is guided into the mold 16 via a flow path inside the injection pipe 11.
[0004]
　The molten metal 21 flowing out from the sliding gate 1 at the bottom of the ladle 14 already has a flow velocity toward the downstream side when passing through the sliding gate 1, and the molten metal 21 is further dropped in the injection pipe 11 in the process of falling. Flow velocity increases. The molten metal 21 poured into the tundish 15 forms a flow that passes through the bottom of the tundish 15 at a high speed, and the non-metal inclusions contained in the molten metal 21 sufficiently float in the tundish 15. The opportunity for separation cannot be obtained, and the non-metal inclusions flow directly into the mold 16 together with the molten metal 21, which causes deterioration of the quality of the slab.
[0005]
　When the flow of the molten metal 21 is swirled in the injection pipe 11, a part of the kinetic energy of the flowing molten metal 21 can be distributed to the swirling flow velocity, and the downward flow velocity of the molten metal 21 can be reduced. As a result, it is known that the maximum flow velocity of the downward flow discharged from the injection pipe 11 into the tundish 15 is reduced, and the turbulence of the flow in the tundish 15 due to the discharge flow can be suppressed. For example, Patent Document 1 discloses a method of providing a swivel imparting mechanism in a long nozzle used for injection from a ladle to a tundish.
[0006]
　When the molten metal 21 is injected into the mold 16 from the injection pipe 11 such as the immersion nozzle 13 via the sliding gate 1 at the bottom of the tundish 15, non-metal inclusions adhere to the flow path inside the immersion nozzle 13. It is known to do. In Patent Document 2, in order to reduce nozzle narrowing and blockage of the flow path in the immersion nozzle, a method of devising the shape of the intermediate nozzle in the process of injecting from the tundish into the mold and imparting a swirling flow in the immersion nozzle. Is disclosed.
[0007]
　Further, Patent Document 3 discloses a method of providing a swivel imparting mechanism (blade) inside a dipping nozzle used for injecting from a tundish into a mold. Further, Patent Document 4 discloses a method of turning the molten steel by providing a notch in the flow path of the sliding gate.
Prior art literature
Patent documents
[0008]
Patent Document 1: Japanese Patent Application Laid-Open No. 2006-346688
Patent Document 2: Japanese Patent Application Laid-Open No. 07-303949
Patent Document 3: Japanese Patent Application Laid-Open No. 2000-237852
Patent Document 4: Japanese Patent Application Laid-Open No. 3615437
Outline of the invention
Problems to be solved by the invention
[0009]
　The methods of Patent Document 1 and Patent Document 4 give a limited turn to the flow near the wall surface, and the obtained turn is weak, and the groove and the notch are melted and the turn grant effect cannot be maintained. It was a problem.
　The method of Patent Document 2 has a problem that the shape of the mechanism for imparting swivel is complicated and it is difficult to manufacture.
　The method of Patent Document 3 has a problem that the swivel imparting mechanism in the immersion nozzle and its surroundings are easily blocked by non-metal inclusions.
[0010]
　The present invention solves such a problem of the prior art, and devises a structure of a sliding gate arranged on the upper part of the injection pipe to provide a swirling flow having sufficient strength in the injection pipe for injecting molten metal. It is an object of the present invention to provide a sliding gate which can be applied without increasing the risk of blockage of a flow path by a compact and simple mechanism.
Means to solve problems
[0011]
　The present invention has been made in view of the above circumstances, and each aspect described later is adopted. In the present invention, an injection pipe such as a long nozzle for injecting molten steel from the radle into the tundish and an injection pipe such as a dipping nozzle for injecting molten metal from the tundish into the mold are collectively referred to as "injection pipe". Call.
[0012]
　The present inventor has repeatedly considered and experimented on a method of solving the problems of the prior art in imparting a flow velocity in the swirling direction to the molten metal flowing down the flow path in the injection pipe to reduce the flow velocity in the downstream direction. .. At that time, from the viewpoint of preventing the flow path from being blocked, it was avoided to interpolate a structure such as a blade that divides the flow path into the flow path. Then, among the parts that constitute the existing flow path including the injection pipe and the sliding gate arranged above it, pay attention to the sliding gate that sharply narrows the flow path and gives a violent flow. By devising the shape, it was decided to give a swirl to the molten metal flow in the injection pipe.
[0013]
　The first reason is that the swivel imparting mechanism can be compactly configured by targeting a small cross section and a high-speed flow narrowed in the sliding gate. The second reason is that when an attempt is made to impart a circumferential flow velocity to the downward flow in the flow path of the injection pipe, the flow in the injection pipe is disturbed, which may promote damage to the refractory of the injection pipe and adhesion of non-metal inclusions. There is. On the other hand, there is less risk of new turbulence in the sliding gate, which originally has a violent flow. Further, by combining the oblique holes in different directions formed in the plurality of plates of the sliding gate, it is possible to realize a complicated flow path structure that is difficult to form with one member.
[0014]
　The present invention has been devised from such a viewpoint, and a swirling flow is obtained by devising the shape of the flow path hole formed in the plate of the sliding gate. In the present invention, it has been noted that the cross-sectional shape of each flow path is not complicated so as not to cause the flow path blockage or the flow path wall melting damage.
[0015]
　That is, the gist of the present invention is as follows.
(1) One aspect of the present invention is a slide plate having a plurality of plates having flow path holes through which molten metal passes, and at least one of the plurality of plates is slidable. It is a sliding gate used for adjusting the flow rate of the molten metal, and the
　flow path holes in each of the plurality of plates are located on the upstream side of the molten metal passing through the surface of the plates. An upstream surface opening is formed on the upstream surface, a downstream surface opening is formed on the downstream surface located on the downstream side, and the downstream surface opening is formed from the center of gravity of the upstream surface opening. When the direction toward the center of gravity is the
　　flow path axis direction, the flow path axis inclination between the vertical downstream direction of the sliding surface, which is the downstream direction perpendicular to the sliding surfaces of the plurality of plates, and the flow path axis direction. The angle α is 5 ° or more and 75 ° or less, and the
　　direction in which the flow path axial direction is projected onto the sliding surface is called the sliding surface flow path axial direction, and the sliding plate of the slide plate when the sliding gate is closed. The sliding direction is called the sliding closing direction, and the angle formed by the sliding surface flow path axial direction with respect to the sliding closing direction clockwise when viewed in the vertical downstream direction of the sliding surface is within a range of ± 180 degrees. It is called the flow path axis rotation angle θ inside, and the flow path axis rotation angle θ is different between the plurality of plates adjacent to each other, and the number of the plurality of plates is an integer N of 1 or more. The total number of plates is N, and the flow path axis rotation angles θ of the plurality of plates are sequentially θ 1 , θ 2 , ... From the plate on the most upstream side to the Nth plate. θ NWhen the angle Δθ n = θ N −θ N + 1 (n is an integer of 1 or more and the number of plates is -1), the angles Δθ n are all 10 ° or more and less than 170 °, or the angle. Both Δθ n are more than −170 ° and less than −10 °.
(2) In the sliding gate according to (1) above, the total number of the plurality of plates may be two or three, and the number of slide plates may be one.
Effect of the invention
[0016]
　According to the above aspect of the present invention, in the sliding gate used for adjusting the flow rate of the molten metal, the flow path axis inclination angle α between the flow path axis direction of the flow path hole and the vertical downstream direction of the sliding surface in each plate. Is 5 ° or more and 75 ° or less, and the sliding surface flow path axial direction in which the flow path axial direction is projected onto the sliding surface differs between the plates, and becomes clockwise or counterclockwise as it goes downstream. Change. According to this configuration, the molten metal forms a swirling flow in the flow path hole of the sliding gate. Further, since the molten metal forms a swirling flow even in the injection pipe on the downstream side of the sliding gate, it is possible to suppress the maximum flow velocity in the downstream direction as compared with the conventional sliding gate.
A brief description of the drawing
[0017]
FIG. 1 is a conceptual longitudinal sectional view showing an example of the relationship between a radle, a tundish, a mold and a sliding gate of a continuous casting apparatus.
2A and 2B are views showing a sliding gate according to an embodiment of the present invention, in which FIG. 2A is a plan view of an upper fixing plate, FIG. 2B is a slide plate, and FIG. 2C is a lower fixing plate. (D) is a front view of a combination of a sliding gate and an injection pipe. (E) is a view taken along the line EE of (D), and (F) is a cross-sectional view taken along the line FE of (A).
FIG. 3 is a diagram showing the sliding gate, in which (A) is an arrow view of AA of (D), (B) is an arrow view of BB of (D), and (C) is (D). CC arrow view, (D) is a front view of a combination of a sliding gate and an injection tube, and (E) is an EE arrow view of (D).
[Fig. 4] Fig. 4 is a diagram showing the flow of molten metal in the sliding gate, in which (A) is an arrow view of AA of (D), (B) is an arrow view of BB of (D), and ( C) is a view taken along the line CC of (D), (D) is a front view of the combination of the sliding gate and the injection tube, and (E) is a view taken along the line EE of (D).
5A and 5B are views showing a modification of the sliding gate according to the above embodiment, in which FIG. 5A is an upper fixing plate, FIG. 5B is a slide plate, and FIG. 5C is a front view of a combination of a sliding gate and an injection pipe. (D) is a view taken along the line DD of (C), and (E) is a cross-sectional view taken along the line EE of (A).
FIG. 6 is a diagram showing another modification of the sliding gate according to the above embodiment, in which (A) is an arrow view of AA of (C) and (B) is an arrow view of BB of (C). (C) is a front view of a combination of a sliding gate and an injection pipe, and (D) is a view taken along the line DD of (C).
7A and 7B are views showing still another modification of the sliding gate according to the above embodiment, showing an example of an upper fixing plate provided in the sliding gate, FIG. 7A is a plan view, and FIG. 7B is a front view. , (C) is a side view, and (D) is a sectional view taken along the line DD of (A).
FIG. 8 is a diagram showing a sliding gate of a comparative example, in which (A) is an upper fixing plate, (B) is a sliding plate, (C) is a front view of a combination of a sliding gate and an injection pipe, and (D) is (D). C) is a view taken along the line DD, and (E) is a cross-sectional view taken along the line EE of (A).
9A and 9B are views showing a sliding gate of a comparative example, in which FIG. 9A is an arrow view of AA, FIG. 9B is an arrow view of BB, and FIG. 9C is a front view of a combination of a sliding gate and an injection tube. FIG. 3D is a view taken along the line DD of FIG.
10A and 10B are views showing a conventional sliding gate, in which FIG. 10A is a plan view of an upper fixing plate, FIG. 10B is a slide plate, and FIG. 10C is a lower fixing plate. (D) is a front view of a combination of a sliding gate and an injection pipe. (E) is a view taken along the line EE of (D), and (F) is a cross-sectional view taken along the line FE of (A).
11A and 11B are views showing a conventional sliding gate, in which FIG. 11A is an arrow view of AA of (D), FIG. 11B is an arrow view of AB of (D), and FIG. ) CC arrow view, (D) is a front view of a combination of a sliding gate and an injection tube, and (E) is an EE arrow view of (D).
Mode for carrying out the invention
[0018]
　An embodiment of the present invention and a modification thereof will be described with reference to FIGS. 1 to 11. In the following description, the same reference numerals are used in order to clearly explain the correspondence between the prior art and the present embodiment and its modifications. However, even if the reference numbers are the same, the description of FIGS. 10 and 11 shows the prior art, and the description of FIGS. 1 to 9 shows an embodiment of the present invention and a modification thereof.
　The sliding gate 1 is used for the purpose of adjusting the flow rate of the molten metal 21 in the process of injecting the molten metal 21 from the ladle 14 to the tundish 15 or from the tundish 15 to the mold 16 in the continuous casting of the molten metal such as steel. In the sliding gate 1 formed by stacking two or three plates 2, each plate 2 is provided with a flow path hole 6. When the slide plate 4 of the plurality of plates constituting the sliding gate 1 is slid and the sliding gate 1 is "open" due to the overlap between the flow path holes 6 of the respective plates 2, the flow path hole 6 is formed. The molten metal 21 circulates from the upstream side to the downstream side of the above. The direction perpendicular to the sliding surface 30 of the plate 2 toward the downstream direction (hereinafter, referred to as the sliding surface vertical downstream direction 32) is usually vertically downward from the top to the bottom. On the other hand, in the case of horizontal continuous casting, the vertical downstream direction 32 of the sliding surface faces the horizontal direction. In the following, basically, a case where the sliding surface 30 is horizontal and the sliding surface vertical downstream direction 32 is vertically downward will be described as an example.
[0019]
　In the case of the conventional configuration, the flow path hole 6 of the plate 2 usually has a cylindrical inner peripheral shape as shown in FIGS. 10 and 11, and the axial direction of the cylinder is 32 in the vertical downstream direction of the sliding surface. It is configured in parallel. On the other hand, in the present embodiment, as shown in FIGS. 2 to 9, the direction in which the central axis of the flow path hole 6 faces is an oblique hole having an angle from the vertical downstream direction 32 of the sliding surface. Further, in the present embodiment, the directions of the oblique holes projected on the sliding surface 30 are appropriately combined so that the directions of the oblique holes are different from each other between the two or three plates. With this configuration, not only the flow toward the downstream side but also the circumferential flow velocity is added to form a swirling flow with respect to the molten metal flow inside the sliding gate 1 and the injection pipe 11 on the downstream side thereof.
[0020]
　As the cross-sectional shape of the flow path hole 6, a cylindrical shape having a perfect circular cross-section perpendicular to the axial direction is usually used. In the sliding gate 1 of the present embodiment, the flow path hole 6 formed in the plate 2 is not limited to a cylindrical shape, and the axial direction of the flow path hole 6 also changes in the plate 2. It doesn't matter if there is one. Therefore, first, the axis of the flow path hole 6 formed in the plate 2 is defined.
[0021]
　First, the flow path hole 6 of the conventional sliding gate 1 will be described with reference to FIG. The sliding gate 1 of FIG. 10 has three plates 2 and is composed of an upper fixing plate 3, a slide plate 4, and a lower fixing plate 5 from the upstream side. Each plate 2 has a cylindrical shape with a perfect circular cross section, and the axial direction of the cylinder is a flow path hole oriented in the downstream direction perpendicular to the sliding surface 30 (hereinafter referred to as the sliding surface vertical downstream direction 32). 6 is formed. The upstream surface of each plate 2 is referred to as an upstream surface 7u, and the downstream surface is referred to as a downstream surface 7d. The figure (upstream surface opening) formed by the inner peripheral surface of the flow path hole 6 on the upstream surface 7u is called an upstream opening 8u. Further, a figure (downstream surface opening) formed on the downstream surface 7d by the inner peripheral surface of the flow path hole 6 is referred to as a downstream opening 8d. In the example shown in FIG. 10, since the cylindrical axis of the flow path hole 6 is perpendicular to the sliding surface 30, in the plan view shown in FIGS. 10A to 10C, the upstream opening 8u It overlaps with the downstream opening 8d. When the shapes of the upstream opening 8u and the downstream opening 8d are regarded as figures, the center of gravity of these figures can be defined. The center of gravity of the upstream surface opening figure is referred to as the upstream opening center of gravity 9u, and the center of gravity of the downstream surface opening graphic is referred to as the downstream opening center of gravity 9d. In the example shown in FIG. 10, since the shape of both the upstream opening 8u and the downstream opening 8d is a perfect circle, the upstream opening center of gravity 9u and the downstream opening center of gravity 9d coincide with the center of the perfect circular figure. Next, the direction that passes through the upstream opening center of gravity 9u and the downstream opening center of gravity 9d and faces the downstream side is defined as the flow path axial direction 10. In the example shown in FIG. 10, the flow path axial direction 10 is the same direction as the sliding surface vertical downstream direction 32. In FIG. 10 (F), the line drawn by the alternate long and short dash line is the flow path axial direction 10.
[0022]
　Next, the flow path hole 6 of the sliding gate 1 of the present embodiment will be described with reference to FIG. The sliding gate 1 of FIG. 2 has three plates 2 and is composed of an upper fixing plate 3, a slide plate 4, and a lower fixing plate 5 from the upstream side. Each plate 2 is formed with a flow path hole 6 having a cylindrical shape having a perfect circular cross section in the axial direction, and the axial direction of the cylinder is inclined from the direction 32 perpendicular to the downstream of the sliding surface. The upper fixing plate 3 will be described as an example with reference to FIGS. 2A and 2F. FIG. 2 (F) is a cross-sectional view taken along the line FF of FIG. 2 (A). Since the axial direction of the cylindrical shape formed by the flow path hole 6 is inclined with respect to the sliding surface perpendicular downstream direction 32, the upstream opening 8u and the downstream opening 8d are different in the plan view of FIG. 2 (A). It is drawn in the same position. Since the cross section in the axial direction is a perfect circle and the axial direction is a cylindrical shape inclined from the vertical downstream direction 32 of the sliding surface, the upstream opening 8u and the downstream opening 8d each form an oval slightly deviated from the perfect circle. doing. However, for convenience, it is drawn as a perfect circle on the drawing. The centroids of the figures of the upstream opening 8u and the downstream opening 8d can be defined as the upstream opening center of gravity 9u and the downstream opening center of gravity 9d, respectively. Further, the flow path axial direction 10 can be determined so as to pass through the upstream opening center of gravity 9u and the downstream opening center of gravity 9d and face the downstream side. In (F) of FIG. 2, the line drawn by the alternate long and short dash line is the flow path axial direction 10. In the example shown in FIG. 2, the flow path axial direction 10 coincides with the axial direction of a cylindrical shape having a perfect circular cross section in the axial direction forming the flow path hole 6. Here, the angle formed by the downstream direction perpendicular to the sliding surface 30 of the plate 2 (the vertical downstream direction 32 of the sliding surface) and the flow path axis direction 10 is defined as the flow path axis inclination angle α. Here, the reason why the center of gravity of the hole is used instead of the center of the circle to determine the direction of the flow path axis is to universally define the direction of the flow path axis even when the shape of the hole is not a perfect circle.
[0023]
　In the example of the prior art shown in FIG. 10, the downstream opening 8d of the upper fixing plate 3 and the upstream opening 8u of the slide plate 4, the downstream opening 8d of the slide plate 4 and the upstream opening 8u of the lower fixing plate 5 are The sliding positions of the slide plates 4 are determined so as to match each other, that is, the sliding gate 1 is in a fully open state (see (D) in FIG. 10). In the sliding gate 1 shown in FIG. 10, the opening degree of the sliding gate 1 can be reduced from the fully open state by moving the slide plate 4 to the left in the drawing. FIG. 11 shows a state in which the opening degree of the same sliding gate 1 as in FIG. 10 is halved. The sliding gate 1 can be fully closed by further moving the position of the slide plate 4 to the left side of the drawing.
　The same applies to the examples shown in FIGS. 2 and 3. In FIG. 2, the sliding gate 1 is fully opened, and the downstream opening 8d of the upper fixing plate 3 and the upstream opening 8u of the slide plate 4, the downstream opening 8d of the slide plate 4 and the upstream opening 8u of the lower fixing plate 5 are shown. , The sliding positions of the slide plate 4 are determined so as to coincide with each other. FIG. 3 shows a state in which the opening degree of the sliding gate 1 is halved with respect to the same sliding gate 1 as in FIG. The direction in which the slide plate 4 slides when the sliding gate 1 is closed is hereinafter referred to as "sliding closing direction 33".
[0024]
　In the present embodiment shown in FIG. 2, the flow path axis direction 10 is tilted at the flow path axis inclination angle α with respect to the sliding surface vertical downstream direction 32. Therefore, when the direction in which the flow path axis direction 10 is projected onto the sliding surface 30 is set to the sliding surface flow path axis direction 31, the sliding surface flow path axis direction 31 can be determined. In each of (A) to (C) and (F) of FIG. 2, the sliding surface flow path axial direction 31 is indicated by a thin arrow. In FIGS. 2A to 2C, the sliding surface flow path axial direction 31 overlaps with the flow path axial direction 10. Further, in the example shown in FIG. 10, since the flow path axis direction 10 faces the sliding surface vertical downstream direction 32, in the plan view shown in FIGS. 10A to 10C, the sliding surface flow path axis is Direction 31 does not appear.
[0025]
　Next, the angular relationship between the sliding surface flow path axial direction 31 and the sliding closing direction 33 is defined. The angle formed by the sliding surface flow path axis direction 31 clockwise with respect to the sliding closing direction 33 in the sliding surface perpendicular downstream direction 32 is called a flow path axis rotation angle θ. The flow path axis rotation angle θ is defined as an angle within the range of ± 180 °. That is, when the sliding surface flow path axial direction 31 becomes an angle (θ') that exceeds + 180 ° clockwise when viewed in the vertical downstream direction 32 of the sliding surface, it is set as "θ = θ'-360 °". The angle θ is defined as a negative value. As the subscript of the angle θ, θ of the most upstream plate 2 is θ 1 , θ of the plate 2 on the downstream side is θ 2 , and θ of the plate 2 on the downstream side is θ 3 . Attach. When expressed as θ N as a representative, N is an integer of 1 or more and means a numerical value up to the number of plates of the sliding gate 1. In the example shown in FIG. 2, the upper fixing plate 3 has an angle θ 1 = −45 °, the slide plate 4 has an angle θ 2 = + 90 °, and the lower fixing plate 5 has an angle θ 3 = −135 °.
[0026]
　Further, in the sliding gate 1, the relationship of the flow path axis rotation angle θ between the two plates 2 in contact with each other is defined as follows. That is, the total number of the plurality of plates 2 is N by using an integer N of 1 or more. Then, the flow path axis rotation angles θ of the plurality of plates 2 are set to θ 1 , θ 2 , ... θ N in order from the plate 2 on the most upstream side to the Nth plate . Then, Δθ n is determined by setting the angle Δθ n = θ N −θ N + 1 (n is an integer of 1 or more and up to the number of plates-1) . Δθ n is defined as an angle in the range of ± 180 degrees, similar to θ N above . That is, when Δθ n becomes an angle exceeding + 180 ° (Δθ n ') , Δθ n is defined as “Δθ n = Δθ n'- 360 °” and Δθ n is defined as a negative value. Also, the angle at which Δθ n is less than −180 ° (Δθ) When n ') is obtained, Δθ n = Δθ n '+ 360 ° and Δθ n is defined as a positive value. As a result, Δθ n becomes a number within the range of ± 180 °. Here, when Δθ n is more than 0 ° and less than + 180 °, it indicates that the flow path axis rotation angle θ N changes counterclockwise from upstream to downstream . On the contrary, when Δθ n is more than −180 ° and less than 0 °, it indicates that the flow path axis rotation angle θ N changes clockwise from the upstream to the downstream . In the example shown in FIG. 2, [Delta] [theta] 1 = theta 1 - [theta] 2 = -135 °, [Delta] [theta] 2 '= theta 2 - [theta] 3 = 225 since it is ° [Delta] [theta] 2 = [Delta] [theta] 2 becomes' -360 ° = -135 ° .. Δθ 1 , Δθ 2 Since all of them are in the range of −180 to 0 °, it indicates that the flow path axis rotation angle θ is changing clockwise.
[0027]
　Based on the above preparations, the conditions to be satisfied by the sliding gate 1 of the present embodiment and the reasons thereof will be described.
[0028]
　In the conventional sliding gate 1, as shown in FIGS. 10 and 11, the flow path axis direction 10 is perpendicular to the sliding surface 30, that is, the flow path axis inclination angle α is 0 ° and has an inclination. I didn't. On the other hand, the first feature of the present embodiment is that the flow path axis direction 10 is tilted with respect to the sliding surface perpendicular downstream direction 32, and the flow path axis tilt angle α is not 0 °. Since the flow path axis is tilted with respect to the sliding surface vertical downstream direction 32, the molten metal flowing in the plate is not only the velocity component in the sliding surface vertical downstream direction 32 but also in the sliding surface vertical downstream direction 32. On the other hand, it has a velocity component at right angles (a velocity component in the horizontal direction in the case of normal continuous casting). In the present embodiment, the flow path axis inclination angle α is 5 ° or more and 75 ° or less. By setting the angle α to 5 ° or more, the molten metal 21 has a sufficient velocity component in the horizontal direction, and as shown below, a swirling flow can be formed in the injection pipe 11. The angle α is preferably 10 ° or more, more preferably 15 ° or more. On the other hand, if the angle α is too large, it is not preferable from the viewpoint of ensuring the strength of the refractory forming the flow path hole 6 and suppressing wear, so the angle α is set to 75 ° or less. The angle α is preferably 65 ° or less, more preferably 55 ° or less.
[0029]
　Regarding the opening condition of the sliding gate 1 during continuous casting, in a steady state where the molten metal level in the tundish 15 is constant and casting is performed at a constant casting speed, the sliding gate 1 and the tundish 15 at the bottom of the radle 14 In each of the sliding gates 1 at the bottom of the sliding gate 1, the opening of the sliding gate 1 is not fully opened (see FIG. 10), but the sliding gate 1 is opened so that casting can be performed in a state where the opening is narrowed (see FIG. 11). Degree selection has been made. In FIG. 11, the opening degree of the sliding gate 1 is 1/2. In this case, the opening area of ​​the sliding gate 1 is calculated to be 0.31 times the opening area of ​​the flow path hole 6 which is a perfect circle. As a result of the small area narrowed down in this way becoming the opening area during steady continuous casting, a flow with a large maximum flow velocity flows in the flow path on the downstream side of the slide plate 4 of the sliding gate 1. It becomes.
[0030]
　FIG. 3 shows the sliding gate 1 when the opening degree of the sliding gate 1 (fully open opening) of the present embodiment having the shape shown in FIG. 2 is changed and the opening degree is halved. (A) of FIG. 3 is a view taken along the line AA of (D). The downstream opening 8d of the upper fixing plate 3 is partially drawn with a solid line and a part with a broken line, and the slide plate 4 is opened upstream. Only the hole 8u (4) is also drawn with a solid line and a broken line. (B) of FIG. 3 is a view taken along the line BB of (D), in which the upstream opening 8u of the slide plate 4 is drawn with a solid line, the downstream opening 8d is drawn with a solid line and a broken line. The upstream opening 8u of the lower fixing plate 5 is also drawn with a solid line and a part with a broken line, and the downstream opening 8d is drawn with a broken line. (C) of FIG. 3 is a view taken along the line CC of (D), and the upstream opening 8u of the lower fixing plate 5 is drawn with a solid line, the downstream opening 8d is drawn with a solid line, and a broken line. ..
　The flow of the molten metal 21 in the flow path hole 6 and the injection pipe 11 of the sliding gate 1 when the opening degree is halved as shown in FIG. 3 will be described with reference to FIG. In FIG. 4, (A) of FIG. 4 is a view taken along the line AA of (D), and the downstream opening 8d of the upper fixing plate 3 is partially drawn with a solid line and a part with a broken line, and the slide plate 4 As for, only the upstream opening 8u is drawn with a solid line and a broken line. (B) of FIG. 4 is a view taken along the line BB of (D), and the position of the downstream opening 8d (3) of the upper fixing plate 3 is indicated by a two-dot chain line, and the upstream opening 8u of the slide plate 4 is shown. Are all solid lines, downstream openings 8d are partially solid lines, and some are drawn with broken lines. It is drawn. FIG. 4C is a view taken along the line CC of FIG. 4D, in which the position of the downstream opening 8d (4) of the slide plate 4 is indicated by a chain double-dashed line, and the upstream opening 8u of the lower fixing plate 5 is shown. Are all solid lines, and the downstream opening 8d is drawn with a solid line and a broken line. Further, the streamline 18 of the molten metal is indicated by a thick line arrow in FIGS. 4A to 4C and a thick broken line arrow in (D) and (E).
[0031]
　Regarding the sliding gate 1 of FIGS. 2 and 3, as described above, the difference Δθ n of the adjacent flow path axis rotation angles θ N is Δθ 1 = Δθ 2 = −135 °, and both Δθ n are Since it is more than -180 ° and less than 0 °, the flow path axis rotation angle θ N from upstream to downstream. Indicates that is changing clockwise. The molten metal flow flowing through the flow path hole 6 of the upper fixing plate 3 flows along the flow path axial direction 10 of the upper fixing plate 3 as shown in FIG. 4A. On the contact surface between the upper fixing plate 3 and the slide plate 4, the downstream opening 8d of the upper fixing plate 3 (two-dot chain line in FIG. 4B) and the upstream opening 8u of the slide plate 4 (in FIG. 4B). It flows downstream in the small cross section of the overlapping portion (opening) with the solid line). In the flow path hole 6 of the slide plate 4, the downstream opening 8d of the upper fixing plate 3 (two-dot chain line in FIG. 4B) and the upstream opening 8u of the slide plate 4 (of FIG. 4B). The molten metal flow flowing out from the small cross section of the overlapping portion (opening) with the solid line) is the inner wall surface (cylindrical surface) of the flow path hole 6 of the slide plate 4 as shown by the streamline 18 in FIG. 4 (B). A swirling flow is formed along the above, and the downstream opening 8d of the slide plate 4 (two-dot chain line in FIG. 4C) and the upstream opening 8u of the lower fixing plate 5 ((C) in FIG. 4) are formed on the downstream side. From the small cross section of the overlapping portion (opening) with the solid line), the flow further flows into the flow path hole 6 of the lower fixing plate 5. In the flow path hole 6 of the lower fixing plate 5, a swirling flow is formed along the inner wall surface (cylindrical surface) of the flow path hole 6 of the lower fixing plate 5 as shown by the streamline 18 in FIG. 4 (C). Then, as it is, it flows out into the injection pipe 11 on the downstream side, and as shown in FIGS. 4D and 4E, the streamline 18 in the flow path 17 maintains the swirling flow in the injection pipe 11. To the downstream side.
[0032]
　When the conventional sliding gate 1 as shown in FIG. 11 is used, all of the kinetic energy of the molten metal flow when flowing out from the opening of the sliding gate 1 is consumed by the flow velocity in the downstream direction. There is. On the other hand, when the sliding gate 1 of the present embodiment as shown in FIG. 3 is used, the kinetic energy of the molten metal flow swirls with the flow velocity in the downstream direction when flowing out from the sliding gate 1, and the injection pipe 11 Since it is dispersed in the turning speed of turning the inner peripheral surface of the above, it is possible to suppress the maximum flow velocity in the downstream direction as compared with the conventional sliding gate 1 shown in FIG. As a result, when the injection pipe 11 is a long nozzle 12, even when the molten metal 21 flows out from the lower end of the injection pipe 11 to the molten metal 21 in the tundish 15, due to the swirling flow in the injection pipe 11, As a result of the presence of the flow velocity component in the radial direction from the lower end of the injection pipe 11, the maximum flow velocity downward from the lower end of the injection pipe 11 can be suppressed.
[0033]
　The flow path axis rotation angles θ N between adjacent plates 2 for forming a swirling flow in the flow path hole 6 of the sliding gate 1 and forming a swirling flow in the injection pipe on the downstream side of the sliding gate 1. The condition of the angle Δθ n , which is the difference between the two, will be described. As mentioned above, Δθ n is defined as an angle within the range of ± 180 °. Here, when Δθ n = −10 ° or less and less than + 10 °, the difference between the flow path axis rotation angles θ N and θ N + 1 is too small to form a swirling flow. On the other hand, when Δθ n is + 170 ° or more or −170 ° or less, the absolute value of Δθ n is too large, which rather hinders the formation of a swirling flow. When the sliding gate 1 has two plates, only Δθ 1 is defined, and it is sufficient that this Δθ 1 satisfies the above condition. When the sliding gate 1 has three or more plates, in addition to Δθ 1 , Δθ 2 and even more Δθ n are defined. And Δθ nAre all required to be 10 ° or more and less than 170 °, or the angle Δθ n must be more than −170 ° and less than −10 °. As a result, when the flow path axial direction 10 of the first and second plates 2 changes clockwise, the third and subsequent plates also change clockwise in the same manner, and the first and second plates 2 of the plate 2 change clockwise. When the flow path axial direction 10 of the eye changes counterclockwise, the third and subsequent sheets also change counterclockwise in the same manner, so that the swirling flow can be effectively formed in the sliding gate 1. A more preferable range of Δθ n is 30 ° or more and less than 165 °, or more than -165 ° and −30 ° or less.
[0034]
　The number of plates 2 forming the sliding gate 1 is preferably two or three. In the examples shown in FIGS. 2 to 4, as described above, the number of plates 2 is three. In FIGS. 5 and 6, the number of plates 2 is two, the first plate from the upstream side constitutes the upper fixing plate 3, and the second plate constitutes the slide plate 4. FIG. 5 shows a case where the opening degree is fully opened, and FIG. 6 shows a case where the opening degree is 1/2. α = 51.95 °, θ 1 = −26.57 °, θ 2 = + 26.57 °, and Δθ 1 = −53.14 °, and a clockwise swirling flow can be formed. The reason why the number of plates 2 forming the sliding gate 1 is preferably two or three is that at least two plates 2 are required to express the drawing mechanism of the sliding gate 1, and four or more plates 2 are used. This is because it is not necessary for adjusting the flow rate, and the cost increases as the number of plates 2 increases.
[0035]
　The flow path hole 6 formed in the plate 2 may be a flow path hole 6 having a shape as shown in FIG. 7. FIG. 7 shows an example of the upper fixing plate 3. From the upstream surface 7u of the plate 2 to the middle of the thickness, the shape of the flow path hole 6 is a cylindrical shape with a perfect circular cross section, and the axis of the cylinder faces the sliding surface perpendicular downstream direction 32. From the downstream surface 7d of the plate 2 to the middle of the thickness, the shape of the flow path hole 6 is a cylindrical shape with a perfect circular cross section, and the axis of the cylinder is formed so as to be inclined from the vertical downstream direction 32 of the sliding surface. .. In the middle of the thickness of the plate 2, the flow path hole 6 from the upstream surface 7u and the flow path hole 6 from the downstream surface 7d are connected without a step. Even in the plate 2 having the flow path hole 6 having such a shape, as shown in FIG. 7D, the center of gravity of the upstream surface opening figure (upstream opening center of gravity 9u) to the downstream surface opening figure. The direction toward the center of gravity (downstream opening center of gravity 9d) can be defined as the flow path axial direction 10.
[0036]
　In the examples and comparative examples shown below, the thickness of the plates 2 constituting the sliding gate 1 is the same, but the thickness may be different for each plate 2, such as the slide plate 4 being the thinnest. Further, in these Examples and Comparative Examples, the shape of the flow path holes at the inlet and outlet of each plate 2 of the sliding gate 1 is a circle of the same size, but even if this is an ellipse or an oval. As long as the provisions of the present invention are satisfied, a swirling flow can be obtained. Alternatively, the opening area may be different between the inlet and outlet of each plate 2.
[0037]
　Regarding the angle α, an angle may be given from the middle, such as 0 ° at the upper part of the upper fixing plate 3 and 30 ° at the lower part. It is also possible to gradually change the angle. The angle α may be the same or different for all plates 2.
Example
[0038]
　Hereinafter, the contents of the present embodiment will be specifically described with reference to examples.
　FIG. 1 shows the configuration of a molten metal continuous casting machine from a ladle 14 (ladle) to a mold 16 (mold). In the embodiment, molten steel is assumed as the molten metal 21. When the present embodiment is applied to the sliding gate 1 of the radle 14, for example, a swirling flow is formed in the injection pipe 11 (long nozzle 12) connected to the downstream side of the sliding gate 1, and the tundish 15 is formed from the lower end of the injection pipe 11. It is expected that the maximum flow velocity of the discharge flow discharged into the molten steel inside is reduced, the flow in the tundish 15 is rectified, and the floating removal of non-metal inclusions is promoted. The shape of the sliding gate 1 of this embodiment is illustrated below.
[0039]
　Here, the plates 2 of the sliding gate 1 having the three plates 2 are referred to as an upper fixing plate 3, a slide plate 4, and a lower fixing plate 5 in this order from the top. In the case of the sliding gate 1 having two plates 2, they are referred to as an upper fixing plate 3 and a slide plate 4 in this order from the top.
[0040]
　The flow path axis inclination angle α formed by the downstream direction perpendicular to the sliding surface 30 of the plate 2 (sliding surface vertical downstream direction 32) and the flow path axis direction 10 and the sliding surface flow path axis direction 31 are perpendicular to the sliding surface. Regarding the flow path axis rotation angle θ (range of ± 180 degrees), which is the angle formed clockwise when viewed in the downstream direction 32, the subscripts 1, 2 (3) are added to the water from the plate 2 on the most upstream side. doing. The flow path axis inclination angle alpha, the most upstream side of the plate alpha to alpha of 2 1 , alpha and alpha of the one downstream side of the plate 2 2 , further alpha one downstream side of the plate 2 alpha 3 sequentially with Number. The flow path axis rotation angle theta, the most upstream theta a theta plate 2 of 1 , a theta of One downstream side of the plate theta 2 , further theta one downstream side of the plate theta 3 the order number and wear.
[0041]
　For the ladle 14 and the tundish 15, the effect of the present invention was confirmed using a 1/1 water model experimental machine of the actual machine. The thickness of each plate 2 of the sliding gate 1 is 35 mm, the shape of the flow path hole 6 formed in the plate 2 is a perfect circle with a diameter of 80 mm, and the flow path axis inclination angle α and the flow path axis rotation angle θ are set to predetermined angles. Is used. The long nozzle 12 as the injection pipe 11 provided below the sliding gate 1 has an inner diameter of 100 mm, and the lower end of the long nozzle 12 is immersed in a water bath in the tundish 15. The height from the water surface in the radle 14 to the sliding gate 1 position is 3 m, the height from the sliding gate 1 at the bottom of the radle 14 to the water surface in the tundish 15 is 1 m, and the position of the slide plate 4 of the sliding gate 1 is adjusted. The opening degree was set to 30 mm (closed by 50 mm from fully open), and water was allowed to flow out from the sliding gate 1 in a steady state while maintaining the water surface position in the tundish 15 at a constant height.
[0042]
　At the lower end position of the long nozzle 12, the flow velocity of the water flowing out from the lower end of the long nozzle 12 into the tundish 15 for each flow direction was measured by the laser Doppler method. At the lower end position of the long nozzle 12, the "swirl flow evaluation result" is displayed in "GOOD" when there is a horizontal flow velocity, and "BAD" is displayed when there is no horizontal flow velocity.
[0043]
[table 1]

[0044]
　In Example A of the present invention (see Table 1 and FIGS. 2 to 4), the upper fixing plate 3 of the three-plate type sliding gate 1 has an oblique hole of θ 1 = −45 °, and the slide plate 4 has θ 2 =. An oblique hole of 90 ° and an oblique hole of θ 3 = −135 ° are formed in the lower fixing plate 5 . The flow path axis inclination angles α 1 to α 3 are shown in Table 1. Depending on the combination, regardless of whether the sliding gate 1 is fully open or narrowed down, a circumferential flow velocity is applied to the molten metal flow, and a swirling flow is provided inside the flow path 17 of the injection pipe 11 attached below the sliding gate 1. Can be formed. The swirling flow evaluation result was GOOD.
　In Example A of the present invention, the lower fixing plate 5 outlet (downstream opening 8d) is located directly below the upper fixing plate 3 inlet (upstream opening 8u). In this case, the present invention can be applied only by replacing the three plates 2 of the sliding gate 1 with the examples of the present invention shown in FIGS. 2 and 3 from the conventional examples shown in FIGS. 10 and 11.
[0045]
　In Example B of the present invention (see Table 1, FIG. 5, and FIG. 6), the upper fixing plate 3 of the two-plate type sliding gate 1 has an oblique hole of θ 1 = −26.57 °, and the slide plate 4 has a θ. 2 = 26.57 ° diagonal hole is drilled. The flow path axis inclination angles α 1 to α 2 are shown in Table 1. Depending on the combination, regardless of whether the sliding gate 1 is fully open or throttled, a circumferential flow velocity is applied to the molten metal flow, and a swirling flow is formed inside the flow path 17 of the injection pipe 11 attached below the sliding gate 1. be able to. In Example B of the present invention, since the sliding locus of the slide plate 4 outlet (downstream opening 8d) is located directly below the sliding locus of the upper fixing plate 3 inlet (upstream opening 8u), the sliding gate hardware can be modified. Minimal. The swirling flow evaluation result was GOOD.
[0046]
　Comparative Example C (see Table 1, FIG. 8 and FIG. 9) has a configuration similar to that of Example B of the present invention, but is an example in which turning cannot be obtained because the difference between θ 1 and θ 2 is 180 °. .. The swirling flow evaluation result was BAD.
　Comparative Example D (see Table 1, FIG. 10 and FIG. 11) is a normal sliding gate 1 in which the flow path axis inclination angles α are all 0 °. The swirling flow evaluation result was BAD.
Industrial applicability
[0047]
　According to the sliding gate of the present invention, the problem of the prior art is solved, and a swirling flow having sufficient strength in the injection pipe for injecting molten metal is increased by a compact and simple mechanism to increase the risk of blockage of the flow path. Can be granted without.
Description of the sign
[0048]
　1 Sliding gate
　2 Plate
　3 Upper fixing plate
　4 Sliding plate
　5 Lower fixing plate
　6 Flow
　path hole 7u Upstream surface (upstream side surface)
　7d Downstream surface (downstream side surface)
　8u Upstream opening (upstream side surface opening)
　8d Downstream opening Hole (downstream surface opening)
　9u Upstream opening center of gravity (upstream surface opening graphic center of gravity)
　9d Downstream opening center of gravity (downstream surface sea groove drawing center of gravity)
10 Flow path axial direction
11 Injection pipe
12 Long nozzle
13 Immersion nozzle
14 Radle
15 Tundish
16 Mold
17 Flow line
18 Stream line
21 Molten metal
30 Sliding surface
31 Sliding surface Flow path axis direction
32 Sliding surface vertical downstream direction
33 Sliding closing direction
　α Flow path axis tilt angle
　θ Flow path axis rotation angle
The scope of the claims
[Claim 1]
　It has a plurality of plates having flow path holes through which the molten metal passes, and at least one of the plurality of plates is a slidable slide plate for adjusting the flow rate of the molten metal. In the sliding gate used, the
　flow path hole in each of the plurality of plates has an upstream surface opening on the upstream surface located on the upstream side of the molten metal passing through the surface of the plate. The downstream side surface opening is formed on the downstream side surface located on the downstream side, and the direction from the center of gravity of the upstream side surface opening figure toward the center of gravity of the downstream side surface opening figure is the flow path axis direction. When,
　　the flow path axis inclination angle α between the sliding surface vertical downstream direction, which is the downstream direction perpendicular to the sliding surfaces of the plurality of plates, and the flow path axis direction is 5 ° or more and 75 ° or less. The
　　direction in which the flow path axis direction is projected onto the sliding surface is called the sliding surface flow path axis direction, and the sliding direction of the slide plate when the sliding gate is closed is called the sliding closing direction. The angle formed by the sliding surface flow path axis direction clockwise with respect to the sliding closing direction is within ± 180 degrees with respect to the flow path axis rotation angle θ. No., the flow path axis rotation angle θ is different between the plurality of plates adjacent to each other, and the number of the plurality of plates is set to N in total by using an integer N of 1 or more, and is the most upstream. From the plate on the side to the Nth plate, the flow path axis rotation angles θ of the plurality of plates are set to θ 1 , θ 2 , ... θ N in order , and the angle Δθ n = θ. When N −θ N + 1 (n is an integer of 1 or more and the number of plates is -1), the angles Δθ n are all 10 ° or more and less than 170 °, or the angles Δθ n are all −170. A
sliding gate characterized by being above ° and below -10 ° .
[Claim 2]
　The sliding gate according to claim 1, wherein the total number of the plurality of plates is two or three, and the number of the slide plates is one.